Electronic part compression bonding apparatus and method

ABSTRACT

An elongation amount of electronic parts to be bonded onto a substrate by thermocompression is accurately controlled, and thereby poor connection of the electronic parts is prevented. An electronic part compression bonding apparatus according to the present invention includes a compression bonding unit ( 41 ) which bonds the electronic parts onto the substrate by thermocompression, a pressure supply unit ( 48 ), a pressure control unit ( 83 ) which controls pressure, a heating unit ( 43 ) which heats the compression bonding unit ( 41 ), a temperature control unit ( 85 ), and a thermocompression bonding control unit ( 80 ) which controls the pressure control unit ( 83 ) and the heating unit ( 43 ) based on thermocompression bonding condition data in which at least one of pressure and heating temperature is variably set during a process from start until completion of a thermocompression bonding operation of the electronic parts. In the thermocompression bonding condition data, the pressure is set to be first pressure in a first stage in a process of the thermocompression bonding operation and second pressure, which is lower than the first pressure, in a second stage that follows the first stag

TECHNICAL FIELD

[0001] The present invention relates to an electronic part compressionbonding apparatus and an electronic part compression bonding method, bywhich electronic parts are bonded onto a substrate by compression. Thepresent invention relates particularly to a technology which preventspoor connection of the electronic parts to the substrate by accuratelycontrolling an elongation amount of the electronic parts to be bondedonto the substrate by thermocompression.

BACKGROUND ART

[0002] Conventionally, an electronic part compression bonding apparatushas been known which mounts electronic parts, each formed by afilm-shaped member, onto a substrate made of glass or the like. Thisapparatus has been known as an electronic part compression bondingapparatus for manufacturing a flat panel display typified by a plasmadisplay panel (PDP).

[0003]FIG. 1 is a plan view showing an example of a glass substrate onwhich electronic parts are mounted by an electronic part compressionbonding apparatus, and FIG. 2 is a side view thereof. The glasssubstrate 1 shown in FIGS. 1 and 2 is formed by adhering two types ofsubstrates 1 a and 1 b having different sizes. In FIG. 2, a plurality ofelectronic parts 2 are mounted on the bottom surface of the uppersubstrate 1 a and the top surface of the lower substrate 1 b,respectively, along lines of each of the substrates 1 throughanisotropic conductive films (hereinafter, referred to as “ACF”) 3.

[0004] In the electronic part compression bonding apparatus formanufacturing this type of glass substrate, the ACFs 3 are adhered onthe glass substrate 1 along the lines where the electronic parts 2 aremounted. Thereafter, the electronic parts 2 are preliminarily attachedto the glass substrate 1 by the use of adhesiveness of the ACFs 3. Thepreliminarily attached electronic parts 2 are then heated and pressed tothe glass substrate 1 using the electronic part compression bondingapparatus, thus connecting leads formed on the glass substrate 1 andthose of the electronic parts 2.

[0005]FIG. 3 shows an example of a conventional electronic partcompression bonding apparatus 10. The electronic part compressionbonding apparatus 10 is provided with a long compression tool 13 whichis raised/lowered by a pressure cylinder 11 and has a built-in heater12, and a back-up tool 15 as a pressure receiving tool which is locatedto face the compression tool 13, raised and lowered by an unillustratedlifting means and has a built-in heater 14.

[0006] Next, a compression bonding procedure by the use of theelectronic part compression bonding apparatus 10 is described.

[0007] First of all, the glass substrate 1 where the electronic parts 2are preliminarily attached is put on an unillustrated substrate stage.The line on the glass substrate 1, which should be bonded with theelectronic parts 2 by compression this time, is positioned to face thecompression tool 13. Next, the back-up tool 15 is raised and supportsthe glass substrate 1 from the bottom, and subsequently orsimultaneously, the compression tool 13 is lowered by the pressurecylinder 11. Accordingly, by pressure applied from the pressure cylinder11 and heat from the heaters 12 and 14, the electronic parts 2preliminarily attached to one of the lines of the glass substrate 1 arebonded at once to the glass substrate 1 by thermocompression through theACFs 3. Upon completion of this thermocompression bonding, thecompression tool 13 is raised and the back-up tool 15 is lowered.

[0008] Thereafter, if there remain the lines on the glass substrate 1,where the electronic parts 2 should be bonded by compression, the lineof the glass substrate 1, which should be bonded with the electronicparts 2 next, is positioned to face the compression tool 13 by drivingthe substrate stage.

[0009] On the other hand, if there remain no lines on the glasssubstrate 1, where the electronic parts 2 should be bonded bycompression, the glass substrate on which the electronic parts 2 arecompletely bonded is whisked off the subsequent stage. Thereafter, theelectronic part compression bonding apparatus 10 receives a new glasssubstrate (glass substrate to which the electronic parts 2 arepreliminarily attached) 1 from the preceding process and repeats thecompression bonding operation mentioned above.

[0010] Incidentally, the film-shaped member that is a base material ofeach of the electronic parts 2 is made of, for example, polyimide resin.Therefore, it is known that the electronic parts 2 elongate duringthermocompression bonding thereof by the electronic part compressionbonding apparatus 10 described earlier. Thus, the electronic parts 2 aremade to have relatively small dimensions, allowing for elongationthereof during thermocompression bonding.

[0011] However, the elongation amount required during thethermocompression bonding is different for each type of the electronicparts 2, more specifically, for each of the thickness, size, shape andthe like of the film-shaped member. Therefore, it has been difficult tosatisfactorily adjust the amounts of elongation which occurs during thethermocompression bonding, with respect to various types of theelectronic parts 2.

[0012] When the actual amount of elongation which occurs during thethermocompression bonding is different from a required amount, theelectronic parts and the glass substrate may be poorly connected to eachother, and this has been a disadvantage.

[0013] Meanwhile, one trend is that leads of the electronic part 2,which are to be connected to the leads of the substrate 1, are becomingincreasingly fine-pitched as a flat panel display and the like hasbecome highly functional. Therefore, there has been a demand for animprovement in accuracy of thermocompression bonding by the electronicpart compression bonding apparatus 10.

[0014] The present invention was accomplished in order to address theproblems described in the foregoing.

[0015] It is an object of the present invention to provide an electronicpart compression bonding apparatus and an electronic part compressionbonding method, which can prevent poor connection of electronic partsand a substrate by accurately adjusting an elongation amount of theelectronic parts when bonding the electronic parts onto the substrate bythermocompression.

DISCLOSURE OF THE INVENTION

[0016] The present invention variably controls pressure and heatingconditions for bonding the electronic parts by compression depending onelongation properties of the electronic parts, while focusing on arelation between the elongation properties of the electronic parts andpressure and heat applied to the electronic parts to be bonded to thesubstrate by thermocompression.

[0017] According to a characteristic of the present invention, providedis an electronic part compression bonding apparatus, comprising: acompression bonding unit which performs thermocompression bonding ofelectronic parts by pressing the electronic parts onto a substrate by araising/lowering operation of a lifting unit; a pressure supply unitwhich applies pressure to the compression bonding unit; a pressurecontrol unit which controls pressure supplied by the pressure supplyunit; a heating unit which is built in the compression bonding unit andheats the compression bonding unit; a temperature control unit whichcontrols a heating value of the heating unit; a substrate support unitwhich is located to face the compression bonding unit and supports thesubstrate during a thermocompression bonding operation by thecompression bonding unit; and a thermocompression bonding control unitwhich controls the pressure control unit and the heating unit based onthermocompression bonding condition data which is stored in a storagesection and in which at least one of pressure and heating temperature isvariably set during a process from start until completion of thethermocompression bonding operation of the electronic part, wherein, inthe thermocompression bonding condition data, the pressure is set tofirst pressure at a first stage of the process of the thermocompressionbonding operation and to second pressure, which is lower than the firstpressure, in a second stage which follows the first stage.

[0018] According to another characteristic of the present invention,provided is an electronic part compression bonding apparatus,comprising: a compression bonding unit which performs thermocompressionbonding of electronic parts by pressing the electronic parts onto asubstrate by a raising/lowering operation of a lifting unit; a pressuresupply unit which applies pressure to the compression bonding unit; apressure control unit which controls pressure supplied by the pressuresupply unit; a heating unit which is built in the compression bondingunit and heats the compression bonding unit; a temperature control unitwhich controls a heating value of the heating unit; a substrate supportunit which is located to face the compression bonding unit and supportsthe substrate during a thermocompression bonding operation by thecompression bonding unit; and a cooling unit which cools a coolingmember which is located in the substrate support unit; and athermocompression bonding control unit which controls the temperaturecontrol unit and the cooling unit based on thermocompression bondingcondition data stored in a storage section.

[0019] According to yet another characteristic of the present invention,provided is an electronic part compression bonding apparatus,comprising: a compression bonding unit which performs thermocompressionbonding of electronic parts by pressing the electronic parts onto asubstrate by a raising/lowering operation of a lifting unit; a pressuresupply unit which applies pressure to the compression bonding unit; apressure control unit which controls pressure supplied by the pressuresupply unit; a heating unit which is built in the compression bondingunit and heats the compression bonding unit; a temperature control unitwhich controls a heating value of the heating unit; a substrate supportunit which is located to face the compression bonding unit and supportsthe substrate during a thermocompression bonding operation by thecompression bonding unit; a thermocompression bonding control unit whichcontrols the pressure control unit and the heating unit based onthermocompression bonding condition data which is stored in a storagesection and in which at least one of pressure and heating temperature isset to be variable during a process from start until completion of thethermocompression bonding operation of the electronic parts; and atemperature detection unit which measures temperature to heat theelectronic parts during a period of the thermocompression bonding andsends first detection data which indicates to the thermocompressionbonding control unit that temperature of the electronic parts hasreached predetermined temperature, wherein, upon receipt of the firstdetection data sent from the temperature detection unit, thethermocompression bonding control unit instructs the pressure controlunit to change the pressure from first pressure to second pressure whichis lower than the first pressure.

[0020] According to yet another characteristic of the present invention,provided is an electronic part thermocompression bonding method, inwhich electronic parts are heated by a heating unit built in acompression bonding unit and pressed onto a substrate byraising/lowering the compression bonding unit to bond the electronicparts onto a substrate by thermocompression, the method comprising;previously storing, in a storage section, thermocompression bondingcondition data in which at least one of pressure and heating temperatureis variably set during a process from start until completion of thethermocompression bonding operation of the electronic parts; andcontrolling pressure supplied to the electronic parts by the compressionbonding unit so that, during the thermocompression bonding operation ofthe electronic parts, the pressure becomes first pressure in a firststage of a process of the thermocompression bonding operation and secondpressure, which is lower than the first pressure, in a second stagewhich follows the first stage, based on the thermocompression bondingcondition data stored in the storage section.

[0021] According to the present invention, at least one of the pressureand temperature applied by a compression tool is variably controlledduring the thermocompression bonding operation of the electronic partsonto the substrate by the compression tool. Thus, compression bondingconditions of a heating tool are changed.

[0022] Specifically, the pressure control unit and the heating unit arecontrolled based on the thermocompression bonding condition data inwhich at least one of the pressure and heating temperature is variablyset during the process from start until completion of thethermocompression bonding operation of the electronic parts. In thethermocompression bonding condition data, the pressure is set to be thefirst pressure at the first stage in the process of thethermocompression bonding operation and to the second pressure, which islower than the first pressure, at the second stage that follows thefirst stage. Thus, an elongation amount of the electronic parts duringthermocompression bonding thereof onto the substrate is accuratelycontrolled.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a plan view showing an example of a glass substrate towhich electronic parts are bonded by thermocompression.

[0024]FIG. 2 is a side view of FIG. 1.

[0025]FIG. 3 is a front view showing an example of a construction of aconventional electronic part compression bonding apparatus.

[0026]FIG. 4 is a cross-sectional side view partially showing aconstruction of an electronic part compression bonding apparatusaccording to an embodiment of the present invention.

[0027]FIG. 5 is a diagram showing an example of a relation betweenapplied pressure and time when bonding the electronic parts bycompression in the embodiment of the present invention.

[0028]FIG. 6 is a diagram showing an example of a relation betweentemperature applied to a compression tool and time when bonding theelectronic parts by compression in the embodiment of the presentinvention.

[0029]FIG. 7 is a diagram showing an example of a relation betweenpressure applied by the compression tool and time in the embodiment ofthe present invention.

[0030]FIG. 8 is a diagram showing a relation between temperature appliedto the compression tool and time in the embodiment of the presentinvention.

[0031]FIG. 9 is a diagram showing an example of operation timing of acooling device in the embodiment of the present invention.

[0032]FIG. 10 is a diagram showing an example of compression bondingconditions in a case where TCPs (tape carrier packages) are used as theelectronic parts.

[0033]FIG. 11 is a diagram showing an example of compression bondingconditions in a case where COFs (chip on films) are used as theelectronic parts.

[0034]FIGS. 12A and 12B are cross-sectional views showing a constructionof an ACF (anisotropic conductive film) which connects the electronicparts and a liquid crystal display.

[0035]FIG. 13 is a diagram showing an example of compression bondingconditions in a case of using an ACF which starts hardening at hightemperature.

[0036]FIG. 14 is a diagram showing an example of compression bondingconditions in a case of using an ACF which starts hardening at lowtemperature.

[0037]FIG. 15 is a timing chart showing a raising/lowering operation ofthe compression tool in the embodiment of the present invention.

[0038]FIG. 16 is a diagram showing an example of conditions of pressureand heat applied to the electronic parts in the embodiment of thepresent invention.

[0039]FIG. 17 is a diagram showing another example of conditions ofpressure and heat applied to the electronic parts in the embodiment ofthe present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0040] An embodiment of the electronic part compression bondingapparatus and the electronic part compression bonding method accordingto the present invention is detailed hereinbelow with reference to FIGS.4 to 17.

[0041]FIG. 4 is a cross-sectional side view partially showing an exampleof a construction of the electronic part compression bonding apparatusaccording to the embodiment of the present invention. Note that, in FIG.4, the same components as those in the conventional apparatus aredenoted with the same reference numerals to omit description thereof.

[0042] In FIG. 4, the electronic part compression bonding apparatus 30according to the embodiment of the present invention includes acompression bonding head unit 40, a pressure receiving unit 60 placed toface the compression bonding head unit 40, a substrate stage 70, and acontrol device 80.

[0043] The compression bonding head unit 40 is provided with a headsection 41, a lifting device 42 which raises and lowers the head section41. In the head section 41, a long compression tool 44 having a built-inheater 43 is fixed to a lifting block 47 which is supported to be ableto move up and down by a base plate 45 through a guide rail 46. Thelifting block 47 is connected to an actuation rod 48 a of an aircylinder 48 which is fixed to the base plate 45. In addition, the aircylinder 48 is provided with a pressure detection section 48 b whichdetects pressure applied to the electronic parts by the compression tool44. The pressure detection section 48 b detects whether the pressureapplied to the electronic parts by the compression tool 44 has reached apredetermined pressure is set in advance. Once it is detected that thepressure has reached the predetermined pressure, the pressure detectionsection 48 b sends a predetermined pressure detection signal to acontrol device 80. Upon receipt of the predetermined pressure detectionsignal sent from the pressure detection section 48 b, the control device80 changes pressure supplied to the compression tool 44.

[0044] The lifting device 42 is constituted of a ball screw 50 which isrotated by a motor 49 supported by a later described frame body 52, anda nut member 51. The nut member 51 is connected to the base plate 45supported to be able to move up and down by the frame body 52 through aguide rail 53.

[0045] The pressure receiving unit 60 has a built-in heater 61 and isalso provided with a back-up tool 62 as a pressure receiving tool whichcan be moved up and down by unillustrated lifting means. Temperaturedetecting means 62 b and 44 b, which detects temperature of theelectronic parts 2 or the glass substrate 1, may be provided in one ofor both of the back-up tool 62 and the compression tool 44. Thetemperature detecting means 62 b and 44 b measures whether thetemperature of the electronic parts 2 or the glass substrate 1 hasreached predetermined temperature which is set in advance. Once thetemperature reaches the predetermined temperature, the temperaturedetecting means 62 b and 44 b sends predetermined temperature detectiondata to the control device 80. Upon receipt of the predeterminedtemperature detection data from the temperature detecting means 62 b and44 b, the control device 80 controls changes of temperature to heat thecompression tool 44 or the back-up tool 62.

[0046] Further, a cooling member 64 included in a cooling device 63 isattached onto a side of the back-up tool 62. The cooling member 64 is,for example, a hollow tube. The cooling device 63 cools down the back-uptool 62 as appropriate by, for example, supplying cold air to thecooling member 64 from a cold air supply device 65.

[0047] Note that, in the pressure receiving unit 60, the back-up tool 62is set so that the top surface of the back-up tool 62 (that is, asurface contacting the glass substrate 1) comes at the same height levelas the bottom surface of the glass substrate 1 supported by thesubstrate stage 70, when the back-up tool 62 is brought to a liftedposition.

[0048] The substrate stage 70 includes a stage 71 which attracts andholds the glass substrate 1 and a moving device 72 which movablysupports the stage 71 in X and Y directions, which are perpendicular toeach other, as well as a direction of rotation (θ direction). Thesubstrate stage 70 receives the glass substrate 1 which has theelectronic parts 2 preliminarily attached thereto through the ACFs 3 andis supplied from the preceding process of a preliminary compressionbonding device or the like. The substrate stage 70 then moves the glasssubstrate 1 to a position where the preliminarily attached electronicparts 2 are bonded by compression to the glass substrate 1 by thecompression tool 44. At the same time, the substrate stage 70 passes theglass substrate 1, in which the compression bonding operation iscompleted, to the following process of a substrate storage device or thelike.

[0049] The control device 80 is provided with a storage section 81. Inaddition, the control device 80 is connected to each of a pressurecontrol section 83 placed between the air cylinder 48 and a compressedair supply source 82, a motor control section 84 which controls rotationof the motor 49, thus controlling an ascent/descent speed of thecompression tool 44, a temperature control section 85 which controls thetemperature of the heater 43, a temperature control section 86 whichcontrols the temperature of the heater 61, the cold air supply device 65which supplies cold air to the cooling member 64, and the moving device72 which moves the stage 71.

[0050] The control device 80 controls pressure of compressed airsupplied to the air cylinder 48 through the pressure control section 83,enabling control of the pressure applied by the compression tool 44while pressing and heating the electronic parts 2. Specifically, the aircylinder 48 constructs compression means which applies pressure to thecompression tool 44.

[0051] Moreover, the control device 80 controls drive of the motor 49through the motor control section 48, enabling control of theascent/descent speed of the compression tool 44.

[0052] Furthermore, the control device 80 controls heating values of theheaters 43 and 61 through the temperature control sections 85 and 86,respectively, enabling control of the temperature of the compressiontool 44 and the back-up tool 62.

[0053] Yet further, the control device 80 controls the cold air supplydevice 65, thus allowing on/off control of cold air to be supplied tothe cooling member 64.

[0054] In the storage section 81, thermocompression bonding conditionsbased on the elongation amount of the electronic parts 2 are stored. Thethermocompression bonding conditions include, for example, a temperaturecondition of the compression tool 44, a condition of pressure applied bythe compression tool, and an impact load application condition, during athermocompression bonding operation period when the electronic parts 2are pressed and heated by the compression tool 44.

[0055] Next, control of the thermocompression bonding conditions in thisembodiment is described in detail.

[0056] First, control to suppress the elongation amount of theelectronic parts 2 is described.

[0057] In general, once pressure applied by the compression tool 44 isincreased, force of constraint of the compression tool 44 to theelectronic parts 2 is increased. Thus, elongation of the electronicparts 2 is suppressed.

[0058]FIG. 5 shows an example of control of the pressure conditions fromthe viewpoint of the above. As shown in FIG. 5, during a period fromstart time to of thermocompression bonding of the electronic parts 2 bythe compression tool 44 until time t1, pressure W3 that is higher by apredetermined amount than pressure W2 required for thermocompressionboding of the electronic parts 2 is applied to the electronic parts 2.Meanwhile, during a period from the time t1 until completion time t2 ofthermocompression bonding, the pressure W2 that is lower than thepressure W3 is applied to the electronic parts 2. Thus, the elongationamount of the electronic parts 2 can be suppressed.

[0059] Note that, when the pressure W3 is too high, an adhesive whichadheres the electronic parts 2 to the glass substrate 1 is pushed outfrom the glass substrate 1, causing poor connection therebetween. Inorder to avoid the poor connection, the appropriate pressure W3 isdecided based on the type and quantity of the adhesive.

[0060] In addition, when the temperature to heat the electronic parts 2increases, a film member which constructs each of the electronic parts 2deforms, causing further elongation of the electronic parts 2.

[0061]FIG. 6 shows an example of temperature condition control from theviewpoint of the above. As shown in FIG. 6, during the period from thestart time t0 of thermocompression bonding of the electronic parts 2 bythe compression tool 44 until the time t1, the electronic parts 2 areheated at heating temperature T1 that is lower by predetermined degreesthan heating temperature T2 required for thermocompression bonding ofthe electronic parts 2. Meanwhile, during the period from the time t1until the completion time t2 of thermocompression bonding, theelectronic parts 2 are heated at heating temperature T2 that is higherthan the heating temperature T1. Thus, the elongation amount of theelectronic parts 2 can be suppressed.

[0062] Further, in a case where both the pressure applied to theelectronic parts 2 and the temperature to heat the same are variablycontrolled, the elongation amount of the electronic parts 2 is furthersuppressed if the pressure is increased to W3 before the time t1 of FIG.6.

[0063] Note that, the predetermined time t1 in FIGS. 5 and 6 may be timeafter a certain period is elapsed from the time t0. In addition, thetime t1 may be decided variably based on the type of electronic parts 2to be bonded onto the glass substrate 1 by thermocompression,temperature of compression bonding, the type of adhesive for adheringthe electronic parts 2 to the glass substrate 1, or the like.

[0064] Second, control to increase the elongation amount of theelectronic parts 2 is described.

[0065] In a case where, for example, the heating temperature applied tothe electronic parts 2 during compression bonding is fixed, the pressureapplied to the electronic parts 2 in the initial stage of thethermocompression bonding operation is set to be smaller than apredetermined pressure required for thermocompression bonding, andthereafter increased to the predetermined pressure. Thus, the elongationamount of the electronic parts 2 is larger than that of the electronicparts 2 that are pressed with the predetermined pressure from theinitial stage.

[0066] On the other hand, in a case where the pressure applied to theelectronic parts 2 by the compression tool 44 is fixed, the electronicparts 2 are heated at a predetermined temperature required forthermocompression bonding, from the initial stage of thethermocompression bonding operation. Thus, the elongation amount of theelectronic parts 2 is larger than that of the electronic parts 2 heatedat the heater temperature which is set to be lower than thepredetermined temperature in the initial stage and thereafter increasedto the predetermined temperature.

[0067] Moreover, in a case where the temperature applied to theelectronic parts 2 and pressure applied thereto by the compression tool44 during thermocompression bonding are fixed, an impact load when thecompression tool 44 contacts the electronic parts 2 (that is, a descentspeed of the compression tool 44) is set small. Thus, the elongationamount of the electronic parts is increased.

[0068] Based on the foregoing findings, in this embodiment, theelongation amount of the electronic parts 2 are optimally adjusted byvariably controlling any one of or a combination of thesethermocompression bonding conditions.

[0069] Next, specific examples of control of the thermocompressionbonding conditions are described respectively.

[0070] 1) Load Control

[0071] When it is desired to increase the elongation amount of theelectronic parts 2, the control device 80 adjusts air pressure suppliedto the air cylinder 48 through the pressure control section 83 so thatthe following is realized. As shown by a solid line in FIG. 7, duringthe period from the start time t0 of the thermocompression bondingoperation until the time t1, the pressure applied to the electronicparts 2 by the compression tool 44 is set to W1 which is smaller thanthe predetermined pressure W2 required for thermocompression bonding.During the following period until the completion time t2, the pressureapplied to the electronic parts 2 is set to the predetermined pressureW2.

[0072] On the contrary, when it is desired to reduce the elongationamount of the electronic parts 2, the control device 80 adjusts airpressure supplied to the air cylinder 48 through the pressure controlsection 83 so that, during a period from the start time t0 of thethermocompression bonding operation until the completion time t2thereof, the pressure applied by the compression tool 44 is set to thepredetermined pressure W2 as shown in by a broken line in FIG. 7.

[0073] Note that, when the elongation amount of the electronic parts 2is adjusted to a larger amount, the control device 80 may control thepressure control section 83 so that the pressure applied to theelectronic parts 2 by the compression tool 44 is gradually increasedfrom the start time t0 of the thermocompression bonding operation asshown by an alternate short and long dash line in FIG. 7. Alternatively,the control device 80 may control the pressure in multistage includingtwo or more stages.

[0074] On the other hand, when the elongation amount of the electronicparts 2 is adjusted to a smaller amount, the control device 80 maycontrol the pressure control section 83 so that the following isrealized. As shown by an alternate long and two short dashes line inFIG. 7, during the period from the start time t0 of thethermocompression bonding operation until the time t1, the pressureapplied to the electronic parts 2 by the compression tool 44 is W3 whichis larger than the predetermined pressure W2. During a period from thetime t1 until the completion time t3 of the thermocompression bondingoperation, the pressure applied to the electronic parts 2 is set to thepredetermined pressure W2.

[0075] 2) Heating Temperature Control

[0076] When it is desired to increase the elongation amounts of theelectronic parts 2, the control device 80 adjusts the heating value ofthe heater 43 through the temperature control section 85 so that thefollowing is realized. As shown by a solid line in FIG. 8, during theperiod from the start time t0 of the thermocompression bonding operationuntil the completion time t2 thereof, the temperature of the compressiontool 44 is maintained at the predetermined temperature T2 required forthe thermocompression bonding.

[0077] On the contrary, when it is desired to reduce the elongationamount of the electronic parts 2, the control device 80 adjusts theheating value of the heater 43 through the temperature control section85 so that the following is realized. As shown by a broken line in FIG.8, during the period from the start time t0 of the thermocompressionbonding operation until the time t1, the temperature of the compressiontool 44 is maintained at temperature T1 which is lower than thepredetermined temperature T2. During the following period until thecompletion time t2 of the compression bonding operation is set to thepredetermined temperature T2.

[0078] Note that, when the elongation amount of the electronic parts 2is adjusted to a larger amount, the temperature control section 85 maybe controlled as follows. As shown by an alternate short and long dashline in FIG. 8, the temperature of the compression tool 44 is maintainedat temperature T3 which is higher than the predetermined temperature T2during the period from the start time t0 of the thermocompressionbonding operation until the time t1.

[0079] On the other hand, when the elongation amount of the electronicparts 2 is adjusted to a smaller amount, the temperature control section85 may be controlled so that the temperature of the compression tool 44is gradually increased from the start time t0 of the thermocompressionbonding operation as shown by an alternate long and two short dashesline in FIG. 8. Alternatively, the temperature of the compression tool44 may be controlled in multistage including two or more stages.

[0080] Furthermore, the control device 80 may perform the temperaturecontrol of both the compression tool 44 and the back-up tool 62 throughthe temperature control section 85.

[0081] In stead of changing the temperature of the compression tool 44and the back-up tool 62, the heating temperature applied to theelectronic parts 2 may be controlled by the use of the cooling member 64which is attached to the back-up tool 62.

[0082]FIG. 9 shows an example of temperature control using the coolingmember 64. As shown in FIG. 9, for example, during the period from thestart time t0 of the thermocompression bonding operation until the timet1, the control device 80 activates the cold air supply device 65 to anON state to supply cold air to the cooling member 64 and drops thetemperature of the back-up tool 62. Even if the temperature of thecompression tool 44 is set to the predetermined temperature T2 from thestart time t0 of the thermocompression bonding operation, due toactivation of the cold air supply device 65, the temperature from thecompression tool 44 is removed during the period from the start time t0of the thermocompression bonding operation until the time t1, by theback-up tool 62 whose temperature has been reduced by the cooling member64. Therefore, the temperature of the electronic parts 2 is preventedfrom increasing and maintained at the temperature T1 that is lower thanthe predetermined temperature T2. When controlling the heatingtemperature applied to the electronic parts 2 by the use of the coolingdevice 63 during the thermocompression bonding operation as mentionedabove, the temperature can be changed swiftly in comparison with thecase where the temperature to heat the electronic parts 2 is controlledby controlling the temperature of the heaters provided in thecompression tool 44 and the back-up tool 62. This is because, timerequired for raising temperature of the heaters 43 and 61 is notnecessary.

[0083] Incidentally, each type of the electronic parts 2 has differentelongation properties.

[0084] Next, an example of the aforementioned pressure and temperaturecontrol based on the type of the electronic parts 2 is described.

[0085] The electronic part used as a driver IC of a liquid crystaldisplay includes, for example, a TCP (tape carrier package) and a COF(chip on film). Both of these parts have a form in which an IC ismounted on a film, and are bonded to a substrate by thermocompressionthrough a connection member.

[0086] In the TCP and COF, thicknesses of base films which elongateduring thermocompression bonding are different. Hence, an elongationamount of each of the base films thereof differs from each other whenbonded by thermocompression under the same conditions.

[0087] For example, when a TCP with a thickness of 75 μm and a COF witha thickness of 40 μm are heated and pressed under the samethermocompression bonding conditions, the elongation of the 40 μm-thickCOF is smaller than that of the TCP.

[0088] In order to compensate the difference of the elongation amounts,the control device 80 controls the temperature and pressure so that theelectronic parts 2 are bonded by thermocompression with pressure andheating temperature shown in FIG. 10 when the electronic parts 2 are theTCPs, and with pressure and heating temperature shown in FIG. 11 whenthe electronic parts 2 are the COFs. Thus, the equal elongation can beobtained in the TCPs and COFs.

[0089] Next, description is provided concerning control of the pressureand heating temperature applied to the electronic parts 2 based onproperties of the connection member which connects the electronic parts2 to the glass substrate 1.

[0090]FIGS. 12A and 12B are views explaining a construction of ananisotropic conductive film (ACF) which is one of the connection membersthat connect the electronic parts 2 to the glass substrate 1. The ACF isgenerally used, for example, in order to connect electronic parts to asubstrate. To be more specific, the ACF 125 is the connection member forthe TCPs 127 which are the electronic parts and the liquid crystaldisplay (LCD) 123 which is the substrate as shown in FIG. 12A. The ACF125 is made of, for example, thermosetting resin with a thickness of 15μm and conductive particles 121 having particle sizes of about 5 μm anduniformly distributed within the thermosetting resin. As shown in FIG.12B, by applying pressure to the TCP 127, lead portions of the TCP 127and the LCD 123 are electrically connected through the conductiveparticles 121. In addition, by heating the TCP 127, the thermosettingresin hardens and thereby the TCP 127 as the electronic part and the LCD123 are mechanically connected.

[0091] Hardening of the ACF has an effect of suppressing the elongationof the electronic parts 2. Specifically, a relation between thecompression bonding temperature and hardening speed varies depending onthe type of the thermosetting resin constructing the ACF. Generally, theelongation amount of the electronic parts 2 is suppressed when the ACFwhich starts hardening at low temperature is used in the initial stageof compression bonding. On the other hand, the electronic parts 2 arefurther elongated when the ACF which starts hardening at hightemperature is used. Therefore, in order to accurately control theelongation amount of the electronic parts 2, it is required to set thethermocompression bonding conditions with consideration of thedifference in ACF hardening properties for different temperature. Forexample, as for the ACF which easily hardens at high temperature, thethermocompression boning is carried out by controlling the pressure andheating temperature as shown in FIG. 13. On the other hand, as for theACF which easily hardens at low temperature, the thermocompressionbonding is carried out by controlling the pressure and heatingtemperature as shown in FIG. 14. Thus, the equal elongation amounts ofthe electronic parts 2 can be obtained in both types of ACFs. When theheating temperature is increased, however, an effect of promotingelongation of the electronic parts 2 and an effect of suppressingelongation of the same due to hardening of the ACF occur at the sametime. Therefore, it is required to decide the thermocompression bondingconditions under consideration of a balance of both effects.

[0092] Note that, setting of the thermocompression bonding conditionsbased on the type of the electronic parts 2 was described in theforegoing. However, the thermocompression bonding conditions may bechanged as appropriate depending on other factors such as thecompression bonding temperature, the type of the adhesive to adhere theelectronic parts 2 to the glass substrate 1, and a material of a memberconstructing the electronic part 2, and then the changed conditions maybe set in the storage section 81.

[0093] 3) Speed Control

[0094]FIG. 15 is a timing chart showing a raising/lowering operation ofthe base plate 45 when bonding the electronic parts 2 bythermocompression. In FIG. 15, the base plate 45 starts descending fromtime point ta when descent starts and then descends at a high speed v1during a period until a time point tb when the compression tool 44reaches a position slightly above the electronic parts 2. After the timepoint tb, the speed is changed to a speed (contacting speed) v2 forpreparation for contacting the electronic parts 2. This speed ismaintained until a time point tc over a contacting time point td. Notethat the compression tool 44 comes into contact with the electronicparts 2 at the contacting point td (which is, at the same time, a timepoint when the thermocompression bonding operation starts). Therefore,the actuation rod 48 a of the air cylinder 48 is pushed back by apredetermined amount due to relative displacement of the compressiontool 44 and the base plate 45. Thereafter, the base plate 45 is stoppedfrom the time point tc until a time point te when the thermocompressionbonding operation is completed, and then raised to a stand-by positionat a speed v3 until a time point tf. Note that these operationsmentioned above are carried out by the control device 80 controllingdrive of the motor 49 through the motor control section 84.

[0095] In the speed control according to this embodiment, the contactingspeed v2 between the time points tb and tc is adjusted.

[0096] For example, when it is desired to increase the elongation amountof the electronic parts 2, the control device 80 controls the speed ofthe motor 49 through the motor control section 84 so that the contactingspeed v2 is reduced. Thus, an impact load applied when the compressiontool 44 comes into contact with the electronic parts 2 is reduced.

[0097] On the other hand, when it is desired to reduce the elongationamount of the electronic parts 2, the control device 80 controls thespeed of the motor 49 through the motor control section 84 so that thecontacting speed v2 is increased. Thus, the impact load applied when thecompression tool 44 comes into contact with the electronic part 2 isincreased. By increasing the impact load, pressure applied when thecompression tool 44 comes into contact with the electronic parts 2 isfurther increased. Therefore, the force of constraint to the elongationof the electronic parts is increased, enabling suppression of theelongation amount of the electronic parts 2.

[0098] Note that, by setting the speeds v1 and v3 to be higher than thecontacting speed v2 in the period of thermocompression bondingoperation, time required for one process can be shortened. Hence,productivity is improved in bonding the electronic parts to thesubstrate by thermocompression.

[0099] Next, with reference to FIGS. 16 and 17, description is givenregarding examples of pressure and heating temperature conditions of theelectronic parts 2 in the cases of adjusting the elongation amount ofthe electronic parts 2 to a larger amount and to a smaller amount.

[0100]FIG. 16 is a diagram showing the states of pressure and heatingtemperature applied to the electronic parts 2 when the elongation amountof the electronic parts 2 is adjusted to a larger amount by adjustingthe pressure applied by the compression tool 44 and temperature duringcompression bonding. Specifically, for example, the pressure applied bythe compression tool 44 is controlled under a condition shown by a solidline in FIG. 7, and the heating temperature of the compression tool 44is controlled under a condition shown by a solid line in FIG. 8.

[0101] According to these conditions, as far as the heating temperatureis concerned, the electronic parts 2 are heated at the predeterminedtemperature T2 required for thermocompression bonding immediately afterthe start time t0 of the thermocompression bonding operation. As far asthe pressure is concerned, the electronic parts 2 are pressed with thepressure W1 which is smaller than the predetermined pressure W2 requiredfor thermocompression bonding, during the period from the time t0 untilthe time t1. Therefore, the force of constraint to elongation of theelectronic parts 2 is small during the period between the time t0 andthe time t1, in comparison with the case where the predeterminedpressure W2 and the predetermined temperature T2 are applied to theelectronic parts 2 from the time t0. Thus, the electronic parts 2 areeasily elongated. As a result, the elongation amount of the electronicparts 2 bonded by thermocompression becomes larger than that of theelectronic parts 2 to which the predetermined pressure and temperatureW2 and T2 are applied from the time t0.

[0102]FIG. 17 is a diagram showing the states of pressure and heatingtemperature applied to the electronic parts 2 when the elongation amountof the electronic parts 2 is adjusted to a smaller amount by adjustingthe pressure applied by the compression tool 44 and temperature duringcompression bonding. Specifically, for example, the pressure applied bythe compression tool 44 is controlled under a condition shown by abroken line in FIG. 7, and the heating temperature of the compressiontool 44 is controlled under a condition shown by a broken line in FIG.8.

[0103] According to these conditions, the predetermined pressure W2required for thermocompression bonding is applied to the electronicparts 2 from the start time t0 of the thermocompression bondingoperation. The temperature of the compression tool 44 is set to thetemperature T1 which is lower than the predetermined temperature T2required for the thermocompression bonding operation, during the periodfrom the time t0 until the time t1. Therefore, elongation of theelectronic parts 2 is small during the period between the time t0 andthe time t1, in comparison with the case where the predeterminedpressure W2 and the predetermined temperature T2 are applied to theelectronic parts 2 from the time t0. As a result, the elongation amountof the electronic parts 2 bonded by thermocompression becomes smallerthan that of the electronic parts 2 to which the predetermined pressureand temperature W2 and T2 are applied from the time t0.

[0104] Thus, according to this embodiment mentioned above, thetemperature condition of the compression tool 44, the pressureconditions by the compression tool 44, the impact load applicationcondition and the like are adjusted. Thus, heating and compressionstates of the electronic parts 2 to be heated during the period of thethermocompression bonding operation can be adjusted. Accordingly, theelongation amount of the electronic parts 2 during the period of thethermocompression bonding operation and the force of constraint to theelongation thereof can be controlled. Thus, the elongation amount of theelectronic parts to be bonded by thermocompression can be accuratelyadjusted, and thereby preventing poor connection of the electronicparts.

[0105] Note that, in the aforementioned embodiment, each of thethermocompression bonding conditions stored in the storage section 81may be set and stored in the storage section 81 by an operator everytime a variable element of the thermocompression conditions, such as thetype of the electronic parts 2, is changed. Alternatively, thethermocompression conditions based on each type of the electronic parts2 are obtained by testing or the like and stored in the storage section81 in advance. Therefore, when the variable element of thethermocompression conditions such as the type of the electronic parts 2is changed, the control device 80 may select the thermocompressionbonding conditions corresponding to the type of the electronic parts 2out of the thermocompression conditions stored in the storage section 81by inputting type information.

[0106] Moreover, it was described in the foregoing example that thedescending speed of the compression tool 44 is controlled to be thecontacting speed v2 during the period between tb and tc shown in FIG.15. However, the contacting speed v2 should be maintained at least untilthe time point td when the compression tool 44 comes into contact withthe electronic parts 2. Therefore, the descending speed of thecompression tool 44 after the time td may be controlled to be adifferent speed from the contacting speed v2, for example, a speedhigher than the contacting speed v2.

[0107] Further, it was described in the foregoing example that cold airis supplied to the cooling member 64 of the cooling device 64 and thusthe temperature of the back-up tool 62 is dropped. However, the coolingmedium to be supplied to the cooling member 64 may not be air but, forexample, water.

[0108] Furthermore, the cooling device 63 may cool down not only theback-up tool 62 but also the compression tool 44. Specifically, thecooling device 64 may be attached to the side of the compression tool44.

[0109] Furthermore, it was described in the foregoing example that theback-up tool 62 is cooled down by the cooling device 63. However,portions which are bonded by compression, such as the electronic parts 2and the glass substrate 1, may be directly cooled down during the periodof the thermocompression bonding operation of the electronic parts 2 bythe compression tool 44. This can be achieved by directly contacting thecooling member 64 to the electronic parts 2 or the glass substrate 1. Asa matter of course, this can also be achieved by blowing cold air from anozzle or the like directly to the electronic parts 2 or the glasssubstrate 1.

[0110] When direct cold air blow is used to cool down the glasssubstrate 1 during the thermocompression bonding, cold air cannot beblown directly to the glass substrate 1 to be cooled down since theglass substrate 1 is sandwiched by the compression tool 44 and theback-up tool 62 which block the cold air. Thus, cooling of the glasssubstrate 1 becomes less efficient. On the contrary, by providing acooling mechanism on the side of the back-up tool 62 on the oppositeside of the compression tool 44 which is a heating mechanism, heatapplied to the glass substrate 1 is removed to the side of the back-uptool 62, thus improving cooling efficiency.

[0111] Moreover, it was described in the forgoing example that theascent/descent speed of the compression tool 44 is changed bycontrolling rotation of the motor 49, and the pressure applied by thecompression tool 44 is changed by controlling air pressure supplied tothe air cylinder 48. However, a single drive device maybe used tocontrol the ascent/descent speed of the compression tool 44 and pressureapplied by the same may be performed.

[0112] Furthermore, needless to say, the material of the substrate isnot limited to glass and the connecting material is not limited to theanisotropic conductive film.

[0113] Note that the present invention is not limited to the foregoingembodiment. Needless to say, various changes and modifications may bemade without departing from the gist of the present invention. All ofthese changes and modifications should be included within the scope ofthe present invention.

INDUSTRIAL APPLICABILITY

[0114] According to the electronic part compression bonding apparatusand method of the present invention, elongation amounts of theelectronic parts can be accurately adjusted, thus preventing poorconnection between the electronic parts and the substrate.

[0115] The electronic part compression bonding apparatus and method ofthe present invention are useful as they can be broadly used fortechnologies related to mounting of the electronic parts on varioustypes of substrates and improve accuracy in electronic part mounting.

1. An electronic part compression bonding apparatus, comprising: a compression bonding unit (41) which performs thermocompression bonding of electronic parts by pressing the electronic parts onto a substrate by a raising/lowering operation of a lifting unit (42); a pressure supply unit (48) which applies pressure to the compression bonding unit (41); a pressure control unit (83) which controls pressure supplied by the pressure supply unit (48); a heating unit (43) which is built in the compression bonding unit (41) and heats the compression bonding unit (41); a temperature control unit (85) which controls a heating value of the heating unit; a substrate support unit (62) which is located to face the compression bonding unit (41) and supports the substrate during a thermocompression bonding operation by the compression bonding unit (41); and a thermocompression bonding control unit (80) which controls the pressure control unit (83) and the heating unit (43) based on thermocompression bonding condition data which is stored in a storage section (81) and in which at least one of pressure and heating temperature is variably set during a process from start until completion of the thermocompression bonding operation of the electronic parts, wherein, in the thermocompression bonding condition data, the pressure is set to first pressure at a first stage of the process of the thermocompression bonding operation and to second pressure, which is lower than the first pressure, in a second stage which follows the first stage.
 2. The electronic part compression bonding apparatus according to claim 1, wherein, in the thermocompression bonding condition data, the heating temperature is set to first heating temperature at the first stage and to second heating temperature, which is higher than the first heating temperature, in the second stage which follows the first stage.
 3. The electronic part compression bonding apparatus according to claim 1, wherein the thermocompression bonding control unit (80) moves from the first stage to the second stage in the process, after predetermined time t is elapsed, and the predetermined time t is variably decided based on any one or more of a type of the electronic parts to be bonded onto the substrate by thermocompression, compression bonding temperature, a type of an adhesive which adheres the electronic parts to the substrate.
 4. The electronic part compression bonding apparatus according to claim 1, further comprising: a speed control unit (84) which controls an ascent/descent speed of the lifting unit (42), wherein, in the thermocompression bonding condition data, a first ascent/descent speed before the compression bonding unit (41) comes into contact with the electronic parts to be bonded onto the substrate by thermocompression and after completion of the thermocompression bonding is set higher than a second ascent/descent speed after the compression bonding unit (41) contacts the electronic parts.
 5. The electronic part compression bonding apparatus according to claim 1, further comprising: a second heating unit (61) which is built in the substrate support unit (62) and heats the substrate support unit (62); and a second temperature control unit (86) which controls a heating value of the second heating unit, wherein the thermocompression bonding control unit (80) controls the second temperature control unit (86) based on the thermocompression bonding condition data stored in the storage section (81).
 6. An electronic part compression bonding apparatus, comprising: a compression bonding unit (41) which performs thermocompression bonding of electronic parts by pressing the electronic parts onto a substrate by a raising/lowering operation of a lifting unit (42); a pressure supply unit (48) which applies pressure to the compression bonding unit (41); a pressure control unit (83) which controls pressure supplied by the pressure supply unit (48); a heating unit (43) which is built in the compression bonding unit (41) and heats the compression bonding unit (41); a temperature control unit (85) which controls a heating value of the heating unit; a substrate support unit (62) which is located to face the compression bonding unit (41) and supports the substrate during a thermocompression bonding operation by the compression bonding unit (41); and a cooling unit (65) which cools a cooling member (64) which is located in the substrate support unit (62); and a thermocompression bonding control unit (80) which controls the temperature control unit (85) and the cooling unit (65) based on thermocompression bonding condition data stored in a storage section (81).
 7. The electronic part compression bonding apparatus according to claim 6, wherein the cooling unit (65) cools the cooling member (64) by supplying cold air to the cooling member (64), and the thermocompression bonding control unit (80) performs on/off control of cold air supply to the cooling member (64) from the cooling unit (65).
 8. The electronic part compression bonding apparatus according to claim 6, further comprising: a second heating unit (61) which is built in the substrate support unit (62) and heats the substrate support unit (62); and a second temperature control unit (86) which controls a heating value of the second heating unit.
 9. An electronic part compression bonding apparatus, comprising: a compression bonding unit (41) which performs thermocompression bonding of electronic parts by pressing the electronic parts onto a substrate by a raising/lowering operation of a lifting unit (42); a pressure supply unit (48) which applies pressure to the compression bonding unit (41); a pressure control unit (83) which controls pressure supplied by the pressure supply unit (48); a heating unit (43) which is built in the compression bonding unit (41) and heats the compression bonding unit (41); a temperature control unit (85) which controls a heating value of the heating unit; a substrate support unit (62) which is located to face the compression bonding unit (41) and supports the substrate during a thermocompression bonding operation by the compression bonding unit (41); a thermocompression bonding control unit (80) which controls the pressure control unit (83) and the heating unit (43) based on thermocompression bonding condition data which is stored in a storage section (81) and in which at least one of pressure and heating temperature is variably set during a process from start until completion of the thermocompression bonding operation of the electronic parts; and a temperature detection unit (44 b) which measures temperature to heat the electronic parts during a period of the thermocompression bonding and sends first detection data which indicates to the thermocompression bonding control unit (80) that temperature of the electronic parts has reached predetermined temperature, wherein, upon receipt of the first detection data sent from the temperature detection unit (44 b), the thermocompression bonding control unit (80) instructs the pressure control unit (83) to change the pressure from first pressure to second pressure which is lower than the first pressure.
 10. The electronic part compression bonding apparatus according to claim 9, further comprising: a pressure detection unit (48 b) which measures pressure applied to the electronic parts during the period of the thermocompression bonding and sends second detection data which indicates to the thermocompression bonding control unit (80) that the pressure applied to the electronic parts has reached predetermined pressure, wherein, upon receipt of the second detection data sent from the pressure detection unit (48 b), the thermocompression bonding control unit (80) instructs the temperature control unit (85) to change the temperature from first temperature to second temperature which is higher than the first temperature.
 11. An electronic part thermocompression bonding method in which electronic parts are heated by a heating unit (43) built in a compression bonding unit (41) and pressed onto a substrate by raising/lowering the compression bonding unit (41) to bond the electronic parts onto the substrate by thermocompression, the method comprising: previously storing, in a storage section (81), thermocompression bonding condition data in which at least one of pressure and heating temperature is variably set during a process from start until completion of a thermocompression bonding operation of the electronic parts; and controlling pressure supplied to the electronic parts by the compression bonding unit (41) so that, during the thermocompression bonding operation of the electronic parts, the pressure becomes first pressure in a first stage of a process of the thermocompression bonding operation and second pressure, which is lower than the first pressure, in a second stage which follows the first stage, based on the thermocompression bonding condition data stored in the storage section (81).
 12. The electronic part thermocompression bonding method according to claim 11, wherein the controlling controls temperature to heat the compression unit (41) so that the temperature becomes first heating temperature in the first stage of the process of the thermocompression bonding operation and second heating temperature, which is higher than the first heating temperature, in the second stage which follows the first stage, based on the thermocompression bonding condition data stored in the storage section (81). 